Process and apparatus for separating gas mixtures

Claim 1

IN A SYSTEM FOR THE LOW-TEMPERATURE SEPARATION OF A HIGHER AND RELATIVELY LOWER-BOILING IMPURITY CONTAINING GAS MIXTURE BY RECTIFICATION IN WHICH DURING NORMAL OPERATION COMPRESSED GAS MIXTURE TO BE RECTIFIED IN A RECTIFICATION ZONE IS COOLED AND CLEANED BEFORE DELIVERY TO THE RECTIFICATION ZONE BY ALTERNATE FLOW IN ONE DIRECTION THROUGH EITHER OF TWO REVERSING PASSAGEWAYS IN A REVERSIBLE HEAT EXCHANGE ZONE WITH AT LEAST MOST OF SUCH IMPURITIES BEING DEPOSITED IN THE REVERSING PASSAGEWAY DURING SUCH GAS MIXTURE INFLOW AND SUBSEQUENTLY REEVAPORATED BY OUTGOING RECTIFICATION PRODUCT FLOWING IN THE OPPOSITE DIRECTION TO SUCH GAS MIXTURE THROUGH THE SAME REVERSING PASSAGEWAY AND SERVING TO AT LEAST PARTIALLY COOL THE GAS MIXTURE, THE INCOMING GAS MIXTURE AND OUTGOING RECTIFICATION PRODUCT STREAMS BEING PERIODICALLY ALTERNATED BETWEEN SAID REVERSING PASSAGEWAYS, AN IMPROVED METHOD OF CONDITIONING SAID RECTIFICATION ZONE COMPRISING THE STEPS OF PROVIDING A BODY OF STORED LIQUID HAVING A COMPOSITION SIMILAR TO ONE OF THE LIQUIDS OF THE RECTIFICATION; HOLDING SUCH LIQUID BODY AT LOW TEMPERATURE; BETWEEN PERIODS OF NORMAL OPERATION OF THE RECTIFICATION, SELECTIVELY PASSING LIQUID FROM SUCH BODY TO SAID REVERSIBLE HEAT EXCHANGE ZONE FOR PASSGE THERETHROUGH TO COOL AND CLEAN INCOMING GAS OF AT LEAST SAID HIGHER-BOILING IMPURITIES, SAID INCOMING GAS BEING DIRECTED THROUGH AT LEAST ONE OF THE REVERSING PASSAGEWAYS OF THE REVERSIBLE HEAT EXCHANGE ZONE; UTILIZING SUCH CLEANED INCOMING GAS FOR CONDITIONING SAID RECTIFICATION ZONE; AND DURING NORMAL OPERATION PROVIDING THE LOW TEMPERATURE REFRIGERATION FOR SAID PROCESS WHICH IS NEEDED IN EXCESS OF THAT REGAINED FROM THE OUTGOING PRODUCTS.